Abstract

The velocity dependent changes in the impedance of flowing blood have been widely reported in the literature. These changes have been suggested as a source of the impedance change of the thorax measured during Impedance Cardiography techniques. In this study, a theoretical model incorporating red blood cell orientation, was developed to predict the impedance of pulsatile blood as it flows through rigid tubes. Experimental measurements were recorded for comparisons with the theoretical model. Bovine blood was pumped through rigid tubes in a mock circulatory system and its impedance and velocity were measured. Experimental and theoretical impedance and velocity waveforms are presented for a range of cardiac parameters such as pulse rate, stroke volume and systolic/ diastolic ratio. Comparisons show that the theoretical model successfully simulated features of the experimental waveforms. These were: 1) a difference between impedance during accelerating and decelerating flow at the same velocity, 2) an instantaneous impedance response to acceleration, and 3) a decay in impedance during deceleration to zero flow. Both the modelled and experimental impedance data also indicate a good cross correlation with the velocity (r=0.73 and 0.65 respectively at a pulse rate of 70 beats per minute).

These databases contain citations from different subsets of available publications and different time periods and thus the citation count from each is usually different. Some works are not in either database and no count is displayed. Scopus includes citations from articles published in 1996 onwards, and Web of Science® generally from 1980 onwards.

Citations counts from the Google Scholar™ indexing service can be viewed at the linked Google Scholar™ search.

Full-text downloads displays the total number of times this work’s files (e.g., a PDF) have been downloaded from QUT ePrints as well as the number of downloads in the previous 365 days. The count includes downloads for all files if a work has more than one.